Recent experiments in which scientists in Japan turned cells from the gums of mice into stem cells, then used those cells to grow deeply layered skin, have given hope for growing functional skin for human patients. The new lab-grown skin was transplanted onto nude mice, where it integrated well and even sprouted hairs.
Currently skin grafts function, but do not have hair follicles or sweat glands, meaning that they don’t work like real skin. The team hopes that within 5 to 10 years their system can grow skin from the cells of burn victims that can be transplanted back onto them. The findings of the studies were reported in the journal Science Advances on April 1.
Senior author of the paper Takashi Tsuji reported, “Up until now, artificial skin development has been hampered by the fact that the skin lacked the important organs, such as hair follicles and exocrine glands, which allow the skin to play its important role in regulation.” He said the new technique allowed the team to grow skin that replicates normally functioning tissue.
Tsuji described the process, which began by taking cells from the gums of mice and converting them to “induced pluripotent stem cells,” or iPSCs, by bathing them in chemicals that essentially reverse the development of the cells, allowing them to divide again as stem cells which can become nearly any type of cell in the body. This technique was discovered in 2006. The new achievement with the technique, however, was getting the cells to form the different layers of skin which allow them to be fully functional.
The layers of the new artificially-grown skin have glands that secrete sweat and oil, and three separate layers, just like normal skin. In the experiment, once the stem cells turned into skin tissue they were implanted into live mice. They then transplanted the cells out of those mice and put them into other mice, where they turned into skin tissue. About 2 weeks after that transplant, hair began to sprout.
One major improvement with the new skin is that the tissue made connections with nerve and muscle tissue, which allowed it to work as normal skin.
Tsuji said he believes the artificial skin takes scientists one step closer to producing actual organs for transplantation in a lab. The tissue could also be used as skin samples for drug and cosmetic company testing, rather than using animals.